The formation and evolution of candidate young globular clusters in NGC 3256

dWe present images of the recent galaxy merger NGC 3256 obtained with the W ide Field Planetary Camera 2 of the Hubble Space Telescope in B and I filte rs. We show that there is a large population of more than 1000 compact, bri ght, blue objects in this galaxy within the 7 kpc x 7 kpc region studied. T hese objects have sizes, colors, and luminosities like those expected for y oung Galactic globular clusters, with ages ranging from a few to several hu ndred megayears. On this basis, we identify at least some fraction of the c ompact, bright, blue objects in NGC 3256 as young globular clusters. The yo ung cluster system makes up a significant fraction of the total luminosity of the galaxy within the region studied-15%-20% in B and half that in I, in dicating a high efficiency of cluster formation on a galaxy-wide scale. In order to determine the properties of this young cluster system, the selecti on effects in size, color, and luminosity are carefully modeled. We find th at the intrinsic color distribution is broad and there is no significant tr end of color with magnitude. The combination of the broad range of observed colors and the lack of a trend of redder colors at fainter magnitudes cann ot be fitted solely by a broad age distribution and/or differential reddeni ng, although the latter is clearly present. The observations can be account ed for by either the preferential depletion/destruction of lower mass clust ers as they age or a very young age (less than or similar to 20 Myr) for th e cluster population, comparable to or less than the dynamical time of the region in which the clusters are observed. We also find that the luminosity function of the young cluster system can be roughly fitted by a power law with an exponent of -1.8, with tentative evidence that it flattens at faint magnitudes. The clusters are compact in size, with typical estimated half- light radii of 5-10 pc, but there is no obvious cutoff for larger radii and only a shallow trend of size with luminosity. We discuss the implications of these results for models of the formation and dynamical evolution of glo bular clusters, as well as for interpretation of the properties of older gl obular cluster systems.